Porous conductor jacket



n NJ 9 i e 1 0 .n 0 50 F 6 r w a a 0% w 3 W r/ 5 4 e e .W Wig e my 7 JJ. R. M LOUGHLIN ETAL POROUS CONDUCTOR JACKET Filed Dec. 24, 1964 Nov.15, 1966 3,286,019 POROUS CONDUCTOR JACKET Joseph R. McLoughlin, BurntHills, and Wendell T. Starr, Schenectady, N .Y., assignors to GeneralElectric Company, a corporation of New York Filed Dec. 24, 1964, Ser.No. 421,007 6 Claims. (Cl. 174-42) Our invention relates to electricaltransmission lines, and more particularly, to an apparatus forpreventing the buildup of moisture on transmission lines.

In the copending patent application of Joseph R. Mc- Loughlin, 14D-3267,S.N. 421,017, entitled, Covering for Power Line Conductors To ReduceWindage, Corona Loss and Radio Frequency Interference, there isdisclosed an apparatus for reducing corona loss, windage and radiofrequency interference of transmission lines. The apparatus is basicallya flat air foil shaped member, which is fastened to an electricaltransmission line to induce streamlined flow of air around and behindthe transmission line to reduce windage, and also to increase theeffective circumference of the transmission line to reduce corona lossthereon. Because the member has a substantially flat top surface whichis in a horizontal plane, there is a tendency for moisture especiallyrainwater to collect thereon. Runoff of this rainwater along the sidesof the member causes an increase in corona loss of the conductor, aswill subsequently be described, instead of a decrease as is desired. Theneed then arises for means to prevent moisture from interfering with theproper functioning of a corona loss reducing attachment for electricaltransmission cables.

Our invention envisions an aerodynamically air foil shaped member whichis attached to a power cable to reduce corona loss and windage thereon,having a plurality of openings through it for the dissipation ofmoisture collected thereon, to prevent this moisture from interferingwith the corona loss and windage reduction functions of the air foilmember.

The chief object of our invention is the provision of a plurality ofopenings through an .air foil member, which is secured to a power cablefor corona loss and windage reduction purposes, from interfering withthe effective operation of the member.

Another object of our invention is the provision of an air foil shapedmember having a cross section with an elongated horizontal configurationwhich fits over a power transmission cable for reducing windage, coronaloss and radio frequency interference thereon, and where said member hasa plurality of openings therethrough for preventing moisture fromforming on the upper surface of the member and interfering with theeffective operation thereof.

Another object of our invention is the provision of an aerodynamicallyshaped member, having a flat upper surface and rounded ends, that fitsover a power cable for reducing corona and windage losses thereon, wherethe member has a plurality of predetermined openings therethrough, forcausing moisture that forms on the fiat upper surface of the member toflow through the member and not over its rounded ends; so as not tointerfere with effective operation of the member in reducing coronalosses.

A further object of our invention is the provision of an aerodynamicallyshaped air foil member, having a substantially fiat upper surface, thatfits over a power cable, which member has a coating for reducing coronalosses and radio frequency interference, and is constructed of a porousmaterial which permits the drainage of moisture therethrough, to preventthe accumulation of moisture on said member.

A United States Patent where said opening prevent moisture These andother objects of our invention will be more readily perceived from thedescription which follows.

One of the features of our invention is an air foil shaped member forreducing windage losses, corona losses and radio frequency interferenceon .a power transmission ca-ble having a plurality of openingstherethrough for dissipating moisture to prevent its interference withthe effective operation of said member in reducing corona losses.

The attached drawing illustrates of our invention in which:

FIGURE 1 is a cross-sectional view of the apparatus of our invention;

FIGURE 2 is a cross-sectional view of a modification of the apparatus ofour invention.

In FIGURE 1 there is shown a cross-sectional view of the areodynamicallyshaped air foil member, having means for the drainage of moisturetherethrough, embodying our invention. The construction includes member2, being constructed of a light weight porous material such aspolystyrene, polyethylene, polypropylene, epoxy, rubber or urethanefoams, having a configuration that includes rounded edges 3 and flat orslightly curved upper and lower surfaces 4 to produce an overallstreamlined shape. Member 2 is secured in a horizontal fashion to cable5 so that the top and bottom surfaces are substantially paral lel to theearth. Since the force of wind is generally in a horizontal or nearlyhorizontal direction, flow is in a streamlined manner over member 2 andeither trailing edge 3, to thereby avoid disruptive vortical flow aroundand behind the member. Windage drag on conductor 5 is thereby reduced byas much as even though the entire member 2 is far larger than member 5alone. This is more fully discussed in the aforementioned application ofMcLoughlin.

For the purposes of reducing corona loss, the ionizing discharge thatoccurs during transmission of high voltages, a thin coating of asemiconductor or conductor is placed around the entire member 2 andconnected electrically with conductor 5 at point 7. The effectivecircumference of the conductor for corona loss purposes then is thecircumference of the entire member 2 and not just the circumference ofconductor 5 alone. A higher voltage then can be applied to conductor 5without the subsequent undesirable corona loss arcing that might occurotherwise. Corona loss is inversely proportional to the size of theconductor being used, so even though conductor 5 has not been increasedin size, the effective circumference of the conductor now becomes thecircum ference of member 2, which is far greater than member 5 alone andthus corona loss is substantially decreased. Radio frequencyinterference is also decreased by this same coating 10 which surroundsthe entire member 2, when it is .a semiconductor. This is also morefully discussed in the aforementioned application of McLaughlin.

Coating 10 may comprise a fine mesh semiconducting Screen completelysurrounding member 2 to provide both the conducting surface forpreventing corona loss and the semiconducting surface for attenuatingradio frequency. Alternatively, surface 10 may consist of aru-bher orplastic such as polyvinyl chloride with carbon lack, or metal particlestherein to provide this semiconducting surface. Coating 10 may also be athick plastic semiconducting sleeve surrounding member 2. In all casesthere are a suflicient plurality of apertures through the coating forthe drainage of moisture therethrough, as will be discussed.

When it rains, or moisture is present in excessive amounts in theatmosphere, there tends to be a buildup of moisture on upper surface 4of member 2 which moispreferred embodiments ture not only adds to theweight of member 2 to interfere with its proper windage function, butalso tends to flow along sides 3 leading to corona discharge at thesepoints, which are the points of highest voltage gradient. In otherwords, as the moisture builds up along sides 3, the radius of curvatureof the water drops in relation to the member becomes very small, and itis at surfaces of small radii where corona discharge takes place. Toprevent this, there. are sufficient holes on top surface 4 throughcoating or member for water to pass therethrough and through member 2,which is porous, to form on the bottom surface where it dissipates tothe surrounding air. The buildup of moisture on top surface 4 is thusprevented and at the same time moisture is prevented fr-om flowing overends 3 and interfering with the proper operation of member 2. Asemiconductor may also be employed for coating 10, with the properresistivity so that attenuation of radio frequency waves along theconductor takes place and radio frequency interference is therebysubstantially reduced. Means are thus provided for preventing anymoisture from accumulating on the member and running off over edges 3 tointerfere with its operation in reducing corona loss on powertransmission cables.

In FIGURE 2 there is shown a cross-sectional view of a modification ofthe apparatus of FIGURE 1. In this mode, upper surface 20 of member 18has a trough-like indentation or depression 21 located in the centerthereof for the collection of water. Trough 21 is positioned overdrainage slots 22 which pass through member 18 and its outer covering sothat Water collected thereon drains through slots 22 to be collected onbottom surface 23 of member 18 where it dissipates to the atmosphere.Member 18 operates in exactly the same manner as the device of FIGURE 1but a specific location is provided where moisture accumulates and isdrained off. Member 18 operates in the same manner as the mode of FIGURE1 to reduce windage losses, corona losses and radio frequencyinterference on a transmission cable. Member 18 also may be chosen fromthe plastic foams as is merriber 2 in FIGURE 1, but since it does nothave to be porous as does member 2 because .there are defined apertures22 therethrough, it may consist of any light weight material, and alsoalternatively may be hollow. It is also noted that upper surface 20 ofmember 18 does not need to contain a plurality of apertures therein butsimply apertures corresponding to holes 22 so that water can properlydrain off. It is further noted that as mentioned with respect to, FIGURE1, a fine mesh screen may be employed as coating 24 or a semiconductingplastic or elastomeric coating or sheath may also be employed,alternatively, as discussed with respect to FIGURE 1. These operate inexactly the same manner as FIGURE 1. The six apertures 22 shown in thedrawing are by way of illustration only'and are not to be construed as alimitation on our invention.

It is now apparent that our invention attains the objec tives set forth.Apparatus embodying the invention is sturdy in construction and Welladapted for use in conjunction with outdoor environments. Prevention ofthe accumulation of moisture on transmission cables and the successfulremoval thereof in a simple and efficient manner is accomplished.

Specific embodiments of our invention have been illustrated but theinvention is not limited thereto since many modifications may be made byone skilled in the art and the appended claims are intended to cover allsuch modifications as fall within the true spirit and scope of ourinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An apparatus for reducing the effect of corona loss and windage on anelectrical conductor comprising an air aerodynamic foil affixed to theconductor in a substantially horizontal plane,

trailing edges on said air foil at both ends thereof positioned toreduce the effects of windage thereon, an upper surface of said air foilpositioned in a horizontal plane, and means for preventing moistureformed on said upper surface from dripping over said edges andinterfering with the effective operation of the air foil. 2.- Anapparatus for reducing the effect of corona loss and windage on anelectrical conductor comprising an air aerodynamic foil having anelongated crosssectional length affixed to the conductor with itscross-sectional length in a substantially horizontal plane,

trailing edges on said air foil at both ends of said cross-sectionallength positioned to reduce the effects of windage thereon, an uppersurface of said air foil positioned in a horizontal plane, and means forpermitting moisture formed on said upper surface to flow through saidair foil to dissipate to the atmosphere without flowing over the edgesand interfering with the effective corona loss operation of the airfoil. 3. An apparatus for reducing the effect of corona loss and windageon an electrical conductor comprising an air foil affixed to theconductor in a substantially horizontal plane, I

trailing edges on said air foil at both ends thereof positioned toreduce the effects of windage thereon, an upper and lower surface ofsaid air foil inter.- connecting said edges and positioned in ahorizontal plane, conductive means coating the outer surfaces includingthe edges of said air foil to increase its effective circumference forreducing corona losses thereon, and porous means for permitting moistureformed on said upper surface to fiow'through said air foil and dissipateto the atmosphere without flowing over the edges and interfering withthe effective corona loss operation of the air foil. 4. An apparatus forreducing the effect of corona loss and windage on an electricalconductor comprising an'air foil affixed to the conductor in asubstantially horizontal plane,

trailing edges on said air foil at both ends thereof, positioned toreduce the effects of windage thereon, an upper and lower surface ofsaid air foil interconnecting said edges and positioned in a horizontalplane, conductive means coating the outer surfaces including the edgesof said air foil to increase its effective circumference for reducingcorona losses thereon, porous foam material, comprising the interior ofsaid air foil, which permits moisture formed on said upper surface toseep through said air foil to the lower surface thereof, and dissipatesto the atmosphere without flowing over the edges and interfering withthe effective corona loss function of said air foil. 5. An apparatus forreducing the effect of corona loss and windage on an electricalconductor comprising an air foil affixed to the conductor'in asubstantially hor-- izontal plane,

trailing edges :on said air foil at both ends thereof,

positioned to reduce the effects of windage therem. an upper surface ofsaid air foil interconnecting said edges and positioned in a horizontalplane,

having an indentation for collecting moisture therein,

conductive means coating the outer surfaces including the edges of saidair foil to increase its effective circumference for reducing coronalosses thereon,

means defining a plurality of apertures for permitting moisture formedin said indentation on said upper surface to flow through said air foilto dissipate to the atmosphere without flowing over the edges andinterfering with the effective corona loss function of the air foil.

6. An apparatus for reducing the effect of corona loss and windage on anelectrical conductor comprising an air foil afi'ixed to the conductor ina substantially horizontal plane,

trailing edges on said air foil at both ends of its cross-sectionallength positioned .to reduce the effects of windage thereon,

an upper and lower surface of said air foil interconnecting said edgesand positioned in a horizontal plane,

conductive means having a plurality of apertures therein, coating theouter surfaces including the edges of said air foil to increase itsefiective circumference for reducing corona losses thereon, and

porous means for permitting moisture formed on said upper surface toflow through said air foil and said conductive means to dissipate to theatmosphere without flowing over the edges and interfering with theefiective corona loss operation of the air foil.

References Cited by the Examiner UNITED STATES PATENTS LEWIS H. MYERS,Primary Examiner.

20 E. GOLDBERG, Assistant Examiner.

1. AN APPARATUS FOR REDUCING THE EFFECT OF CORONA LOSS AND WINDAGE ON ANELECTRICAL CONDUCTOR COMPRISING AN AIR AERODYNAMIC FOIL AFFIXED TO THECONDUCTOR IN A SUBSTANTIALLY HORIZONTAL PLANE, TRAILING EDGES ON SAIDAIR FOIL AT BOTH ENDS THEREOF POSITIONED TO REDUCE THE EFFECTS OFWINDAGE THEREON, AN UPPER SURFACE OF SAID AIR FOIL POSITIONED IN AHORIZONTAL PLANE, AND MEANS FOR PREVENTING MOISTURE FORMED ON SAID UPPERSURFACE FROM DRIPPING OVER SAID EDGES AND INTERFERING WITH THE EFFECTIVEOPERATION OF THE AIR FOIL.